/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.core.construction;



import com.fasterxml.jackson.core.TreeNode;

import com.fasterxml.jackson.core.type.TypeReference;

import com.fasterxml.jackson.databind.ObjectMapper;

import com.bff.gaia.unified.sdk.options.PipelineOptions;

import com.bff.gaia.unified.sdk.util.common.ReflectHelpers;

import com.bff.gaia.unified.vendor.grpc.v1p13p1.com.google.protobuf.InvalidProtocolBufferException;

import com.bff.gaia.unified.vendor.grpc.v1p13p1.com.google.protobuf.Struct;

import com.bff.gaia.unified.vendor.grpc.v1p13p1.com.google.protobuf.util.JsonFormat;

import com.bff.gaia.unified.vendor.guava.com.google.common.base.CaseFormat;

import com.bff.gaia.unified.vendor.guava.com.google.common.collect.ImmutableMap;



import java.io.IOException;

import java.util.HashMap;

import java.util.Iterator;

import java.util.Map;



/**

 * Utilities for going to/from Runner API pipeline options.

 *

 * <p>TODO: Make this the default to/from translation for PipelineOptions.

 */

public class PipelineOptionsTranslation {

  private static final ObjectMapper MAPPER =

      new ObjectMapper()

          .registerModules(ObjectMapper.findModules(ReflectHelpers.findClassLoader()));



  /** Converts the provided {@link PipelineOptions} to a {@link Struct}. */

  public static Struct toProto(PipelineOptions options) {

    Struct.Builder builder = Struct.newBuilder();



    try {

      // TODO: Officially define URNs for options and their scheme.

      TreeNode treeNode = MAPPER.valueToTree(options);

      TreeNode rootOptions = treeNode.get("options");

      Iterator<String> optionsKeys = rootOptions.fieldNames();

      Map<String, TreeNode> optionsUsingUrns = new HashMap<>();

      while (optionsKeys.hasNext()) {

        String optionKey = optionsKeys.next();

        TreeNode optionValue = rootOptions.get(optionKey);

        optionsUsingUrns.put(

            "unified:option:"

                + CaseFormat.LOWER_CAMEL.to(CaseFormat.LOWER_UNDERSCORE, optionKey)

                + ":v1",

            optionValue);

      }



      // The JSON format of a Protobuf Struct is the JSON object that is equivalent to that struct

      // (with values encoded in a standard json-codeable manner). See Unified PR 3719 for more.

      JsonFormat.parser().merge(MAPPER.writeValueAsString(optionsUsingUrns), builder);

      return builder.build();

    } catch (IOException e) {

      throw new RuntimeException("Failed to convert PipelineOptions to Protocol", e);

    }

  }



  /** Converts the provided {@link Struct} into {@link PipelineOptions}. */

  public static PipelineOptions fromProto(Struct protoOptions) {

    try {

      Map<String, TreeNode> mapWithoutUrns = new HashMap<>();

      TreeNode rootOptions = MAPPER.readTree(JsonFormat.printer().print(protoOptions));

      Iterator<String> optionsKeys = rootOptions.fieldNames();

      while (optionsKeys.hasNext()) {

        String optionKey = optionsKeys.next();

        TreeNode optionValue = rootOptions.get(optionKey);

        mapWithoutUrns.put(

            CaseFormat.LOWER_UNDERSCORE.to(

                CaseFormat.LOWER_CAMEL,

                optionKey.substring("unified:option:".length(), optionKey.length() - ":v1".length())),

            optionValue);

      }

      return MAPPER.readValue(

          MAPPER.writeValueAsString(ImmutableMap.of("options", mapWithoutUrns)),

          PipelineOptions.class);

    } catch (IOException e) {

      throw new RuntimeException("Failed to read PipelineOptions from Protocol", e);

    }

  }



  /** Converts the provided Json{@link String} into {@link PipelineOptions}. */

  public static PipelineOptions fromJson(String optionsJson) {

    try {

      Map<String, Object> probingOptionsMap =

          MAPPER.readValue(optionsJson, new TypeReference<Map<String, Object>>() {});

      if (probingOptionsMap.containsKey("options")) {

        // Legacy options.

        return MAPPER.readValue(optionsJson, PipelineOptions.class);

      } else {

        // Fn Options with namespace and version.

        Struct.Builder builder = Struct.newBuilder();

        JsonFormat.parser().merge(optionsJson, builder);

        return fromProto(builder.build());

      }

    } catch (IOException e) {

      throw new RuntimeException("Failed to read PipelineOptions from JSON", e);

    }

  }



  /** Converts the provided {@link PipelineOptions} into Json{@link String}. */

  public static String toJson(PipelineOptions options) {

    try {

      return JsonFormat.printer().print(toProto(options));

    } catch (InvalidProtocolBufferException e) {

      throw new RuntimeException("Failed to convert PipelineOptions to JSON", e);

    }

  }

}